ES2542610T3 - Preparation process of 4- {4 - [({[4-chloro-3- (trifluoromethyl) -phenyl] amino} carbonyl) amino] -3-fluorophenoxy} -N-methylpyridine-2-carboxamide, its salts and monohydrate - Google Patents

Abstract

A process for preparing the monohydrate of the compound of formula (I) ** Formula ** by treating the compound of formula (IV) ** Formula ** with the compound of formula (V) ** Formula ** in a reaction mixture and subsequently the compound of the formula (I) dissolved with an acid is treated to form a salt of the compound of the formula (I) that precipitates in the solution containing the compound of the formula (I) dissolved and subsequently said salt of the compound of formula (I) is then treated with an aqueous basic solution to precipitate the monohydrate of the compound of formula (I).

Description

image 1

image2

image3

image4

image5

image6

10

fifteen

twenty

25

30

35

E11712881

07-14-2015

In order to provide a highly purified version of the compound of the formula (II) it is dissolved in a suitable organic solvent, treated with an acid that is generated in situ by adding a protic substance and an acid precursor, precipitated as a salt of the compound of the formula (II), preferably the hydrochloric acid salt of the compound of the formula (II) and is neutralized by adding an aqueous solution of a base.

For that purpose, the initial compound 4-chloro-N-methyl-2-pyridinecarboxamide is dissolved in a suitable organic solvent, preferably in toluene and treated with an acid that is generated in situ by adding a protic substance, for example water and / or an alcohol, preferably an alcohol and an acid precursor, preferably an acyl chloride, for example in 5 to 60 minutes, preferably in 10 to 30 minutes, to generate the corresponding acid in situ. Preferably, the protic substance is added first. The 4-chloro-N-methyl-2-pyridinecarboxamide salt, preferably the 4-chloro-N-methyl-2-pyridinecarboxamide hydrochloric acid salt, can be isolated by precipitation. Such purified salt of 4-chloro-N-methyl-2-pyridinecarboxamide is dissolved in a suitable organic solvent, preferably in toluene and neutralized by adding an aqueous solution of a base, preferably an aqueous solution of sodium hydroxide. After phase separation, the organic phase is optionally concentrated under reduced pressure and a suitable organic solvent, preferably 1-methyl-2-pyrrolidinone, is added for the preparation of a solution that can be used directly for the preparation of the compound of the formula (IV) as described above.

Suitable organic solvents in the process for the preparation of 4-chloro-N-methyl-2-pyridinecarboxamide include but are not limited to tetrahydrofuran, toluene, ethyl acetate, dioxane, methyl tert-butyl ether, dimethoxyethane, dimethylsulfoxide, dimethylformamide, 1-methyl -2-pyrrolidinone or mixtures of the solvents mentioned. More preferably, tetrahydrofuran, toluene and mixtures thereof are used.

According to the present invention, alcohols are organic substances that carry at least one hydroxyl group. Alcohols include but are not limited to methanol, ethanol, n-propanol, isopropanol, n-butanol, secbutanol, isobutanol, n-pentanol, glycerol or a mixture thereof. Preferably, methanol, ethanol, isopropanol are used as alcohols in the present process.

In order to prepare the acid in situ suitable precursors include but are not limited to halides of organic acids, preferably acyl halides such as acyl chlorides and acyl bromides, more preferably acetyl chloride, acetyl bromide, propionyl chloride. or propionyl bromide, most preferably acetyl chloride.

Preference is given to an in situ preparation of the acid without water.

Alternatively, the compound of formula (II) and its hydrochloric acid salt can be prepared as described in WO 05/009961 or in Bankston et al. (Organic Process Research & Development, 2002, 6, 777781).

The compound of the formula (V) which is 4-chloro-3-trifluoromethyl-phenylisocyanate can be prepared as described in WO 00/42012.

Abbreviations:

ICD

direct chemical ionization (in MS)

DMF

dimethylformamide

DMSO

dimethylsulfoxide

EI

electronic impact ionization (in MS)

IE

electrospray ionization (in MS)

h

hours)

min

minute (s)

m.p.

melting point

EM

mass spectrometry

NMR

nuclear resonance spectroscopy

THF

tetrahydrofuran

Work examples:

1 H NMR spectra were recorded at room temperature using Bruker spectrometers. Deuterated dimethylsulfoxide was used as solvent including tetramethylsilane as internal standard (if not mentioned in

8 5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

E11712881

07-14-2015

another way).

MS spectra were recorded using Waters and Applied Biosystems spectrometers. The relative signal strength is indicated (in percentage based on the base peak).

HPLC was carried out using HP 1100 from Hewlett Packard. The defined conditions are indicated in the respective working examples.

Preparation of 4- {4 - [({[4-chloro-3- (trifluoromethyl) phenyl] amino} carbonyl) amino] -3-fluorophenoxy} -N-methylpyridine-2-carboxamide, its hydrochloride and its monohydrate

Stage 1:

4-Chloro-N-methyl-pyridine-2-carboxamide hydrochloride:

420 g of a solution of 4-chloro-N-methylpyridine-2-carboxamide (prepared according to WO2006 / 034796) in toluene (approx. 30% w / w) and 48.8 g of ethanol were charged a reaction flask. 67.2 g of acetyl chloride were added with stirring to such an extent that the temperature of the reaction mixture did not exceed 30 ° C. After further stirring at room temperature for 1.5 h, the product was filtered off, washed with toluene (212 g) and dried under reduced pressure (30 ° C, 8,000 pascals (80 mbar)). Thus, 156 g (quantitative yield) of 4-chloro-N-methyl-pyridine-2-carboxamide hydrochloride were obtained.

Mp .: 173.5-174.5 ° C

1H NMR (500 MHz, DMSO-d6): δ [ppm] = 2.93 (d, 3H), 7.79-7.97 (m, 1H), 8.13-8.26 (m, 1H ), 8.71 (d, 1H), 9.03 (sa, 1H), 13.16 (sa, 1H).

MS [INN, NH3]: m / e = 171 [M + H] + (M = free base).

HPLC: stationary phase: Nucleodur Gravity C18 (150 mm long, 3 mm ID, 3.0 µm particle size); mobile phase A: 1.15 g of di-ammonium hydrogen phosphate + 0.68 ml of o-phosphoric acid (85% in water) / 1 l of water; mobile phase B: acetonitrile; UV detection at 254 nm; oven temperature: 45 ° C, injection volume: 3 µl, flow: 0.5 ml / minute; linear gradient: 5% of B → 80% of B (20 minutes), 10 minutes of maintenance time at 80% of B; purity:> 98% (Tr = 17.9 minutes).

Stage 2:

4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide

Procedure 2a:

A reaction flask was charged with a stirrer with 41.4 g of 4-chloro-N-methyl-pyridine-2-carboxamide hydrochloride and 100 g of toluene as solvent. After the addition of 68.4 g of water and 19.6 g of an aqueous sodium hydroxide solution (45% w / w), the reaction mixture was stirred for 30 minutes. The two phases were separated and the aqueous phase was discarded. The organic phase was concentrated by vacuum distillation and toluene was replaced with 1-methyl-2-pyrrolidinone (70 g) to provide a solution of 4-chloro-N-methyl-pyridine-2-carboxamide in 1-methyl-2-pyrrolidinone.

A second reaction flask was charged with agitator with 26.7 g of 4-amino-3-fluorophenol and 100 g of 4-methyl-2pentanone. Heating under reflux and stirring additionally for 1 hour the water was removed by azeotropic distillation. The excess of 4-methyl-2-pentanone was then removed by vacuum distillation and replaced with 1-methyl-2-pyrrolidinone (70 g) to prepare a solution containing the imine compound according to formula (III). To the resulting reaction mixture was added the solution of 4-chloro-N-methyl-pyridine-2-carboxamide in 1-methyl-2-pyrrolidinone. The reaction mixture was heated to about 100 ° C. 123.2 g of potassium t-butoxide in tetrahydrofuran (20% w / w) (in approximately 70 minutes) were added dropwise while the tetrahydrofuran was removed by distillation. The reaction mixture was then stirred for an additional 3 hours at 100 ° C completing the reaction. After adjusting to 80 ° C, 350 ml of toluene, 392 ml of water and 8 g of acetic acid were added. The mixture was stirred for 10 minutes at 80 ° C, cooled to 50 ° C and seeded with crystals of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide. After cooling to 0 ° C the suspension was stirred for approximately 30 minutes. The product was filtered off, washed with methanol / water (1: 3 v / v, 144 ml) and dried under reduced pressure (30 ° C, 8,000 pascals (80 mbar)). In this way 40.7 g (78% of theory) of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide were obtained as brown crystals.

Mp .: 140.5-141.2 ° C

1H NMR (400 MHz, DMSO-d6): δ [ppm] = 2.86 (d, 3H), 5.24-5.35 (s, 2H), 6.80-6.86 (m, 1H ), 6.89-6.99 (m, 1H), 7.01-7.09 (m, 1H), 7.09-7.15 (m, 1H), 7.45 (d, 1H), 8.49 (d, 1 H), 8.75-8.85 (m, 1 H).

MS [ES]: m / e = 262 [M + H] +

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

E11712881

07-14-2015

HPLC: stationary phase: Agilent Zorbax SB-AQ (150 mm long, 3 mm ID, 3.5 µm particle size); mobile phase A: 1.40 g of di-potassium hydrogen phosphate + 5.8 ml of o-phosphoric acid (8.5% in water) / 1 l of water; mobile phase B: acetonitrile; UV detection at 268 nm; oven temperature: 50 ° C, injection volume: 3 µl, flow rate: 0.8 ml / minute; linear gradient in two stages: 10% of B → 37% of B (10 minutes), 37% of B → 80% of B (10 minutes), 10 minutes of maintenance time at 80% of B; purity:> 97% (Tr = 9.2 minutes).

Procedure 2b:

A reaction flask was charged with a stirrer with 41.4 g of 4-chloro-N-methyl-pyridine-2-carboxamide hydrochloride and 100 g of toluene as solvent. After the addition of 68.4 g of water and 19.6 g of an aqueous sodium hydroxide solution (45% w / w) the reaction mixture was stirred for 30 minutes. The two phases were separated and the aqueous phase was discarded. The organic phase was concentrated by vacuum distillation and toluene was replaced by 1-methyl-2-pyrrolidinone (70 g) to provide a solution of 4-chloro-N-methyl-pyridine-2-carboxamide in 1-methyl-2-pyrrolidinone.

A second reaction flask was charged with a stirrer with 26.7 g of 4-amino-3-fluorophenol and 100 g of 3-methyl-2butanone. Heating at reflux and stirring additionally for 3 hours the water was removed by azeotropic distillation. The excess of 3-methyl-2-butanone was then removed by vacuum distillation and replaced with 1-methyl-2-pyrrolidinone (70 g) preparing a solution containing the imine compound according to formula (III). To the resulting reaction mixture was added the solution of 4-chloro-N-methyl-pyridine-2-carboxamide in 1-methyl-2-pyrrolidinone. The reaction mixture was heated to about 100 ° C. 123.2 g of potassium t-butoxide in tetrahydrofuran (20% w / w) (in about 3 hours) were added dropwise while the tetrahydrofuran was removed by distillation. The reaction mixture was then stirred for an additional 2.5 hours at 100 ° C to complete the reaction. After adjusting to 80 ° C, 350 ml of toluene, 392 ml of water and 8 g of acetic acid were added. The mixture was stirred for 10 minutes at 80 ° C, cooled to 50 ° C and seeded with crystals of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide. After cooling to 0 ° C the suspension was stirred for approximately 30 minutes. The product was filtered off, washed with methanol / water (1: 3 v / v, 144 ml) and dried under reduced pressure (30 ° C, 8,000 pascals (80 mbar)). In this way 44.4 g (84% of theory) of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide were obtained as light brown crystals.

Mp .: 142.2-142.8 ° C

1H NMR (400 MHz, DMSO-d6): δ [ppm] = 2.83 (d, 3H), 5.27 (s, 2H), 6.78-6.85 (m, 1H), 6, 86-6.94 (m, 1H), 7.017.07 (m, 1H), 7.09-7.14 (m, 1H), 7.41 (d, 1H), 8.49 (d, 1H) , 8.71-8.87 (m, 1 H).

MS [ES]: m / e = 262 [M + H] +

HPLC: stationary phase: Agilent Zorbax SB-AQ (150 mm long, 3 mm ID, 3.5 µm particle size); mobile phase A: 1.40 g of di-potassium hydrogen phosphate + 5.8 ml of o-phosphoric acid (8.5% in water) / 1 l of water; mobile phase B: acetonitrile; UV detection at 268 nm; oven temperature: 50 ° C, injection volume: 3 µl, flow: 0.8 ml / minutes; linear gradient in two stages: 10% of B → 37% of B (10 minutes), 37% of B → 80% of B (10 minutes), 10 minutes of maintenance time at 80% of B; purity:> 99% (Tr = 9.1 minutes).

Procedure 2c:

A reaction flask was charged with a stirrer with 41.4 g of 4-chloro-N-methyl-pyridine-2-carboxamide hydrochloride and 100 g of toluene as solvent. After the addition of 68.4 g of water and 19.6 g of an aqueous sodium hydroxide solution (45% w / w) the reaction mixture was stirred for 30 minutes. The two phases were separated and the aqueous phase was discarded. The organic phase was concentrated by vacuum distillation and toluene was replaced with 1-methyl-2-pyrrolidinone (70 g) to provide a solution of 4-chloro-N-methyl-pyridine-2-carboxamide in 1-methyl-2-pyrrolidinone.

A second reaction flask was charged with a stirrer with 26.7 g of 4-amino-3-fluorophenol, 73 g of cyclohexane and 20.6 g of cyclohexanone. Heating at reflux and stirring additionally for 3 hours the water was removed by azeotropic distillation. The solvent cyclohexane and excess cyclohexanone were then removed by vacuum distillation and replaced with 1-methyl-2-pyrrolidinone (70 g) to prepare a solution containing the imine compound according to formula (III). To the resulting reaction mixture was added the solution of 4-chloro-N-methylpyridine-2-carboxamide in 1-methyl-2-pyrrolidinone. The reaction mixture was heated to about 100 ° C. 126 g of potassium t-butoxide in tetrahydrofuran (20% w / w) (in about 40 minutes) were added dropwise while tetrahydrofuran was removed by distillation. The reaction mixture was then stirred for an additional 3 hours at 100 ° C to complete the reaction. After adjusting to 80 ° C, 350 ml of toluene, 392 ml of water and 8 g of acetic acid were added. The mixture was stirred for 10 minutes at 80 ° C, cooled to 50 ° C and seeded with crystals of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide. After cooling to 3 ° C, the suspension was stirred for approximately 30 minutes. The product was filtered off, washed with methanol / water (1: 3 v / v, 144 ml) and dried under reduced pressure (30 ° C, 8,000 pascals (80 mbar)). Thus, 40.2 g (76% of theory) of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide were obtained as light brown crystals.

Mp .: 141 ° C

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

E11712881

07-14-2015

1H NMR (400 MHz, DMSO-d6): δ [ppm] = 2.83 (d, 3H), 5.27 (s, 2H), 6.78-6.85 (m, 1H), 6, 86-6.94 (m, 1H), 7.017.07 (m, 1H), 7.09-7.14 (m, 1H), 7.41 (d, 1H), 8.49 (d, 1H) , 8.71-8.87 (m, 1 H).

MS [ES]: m / e = 262 [M + H] +

HPLC: stationary phase: Agilent Zorbax SB-AQ (150 mm long, 3 mm ID, 3.5 µm particle size); mobile phase A: 1.40 g of di-potassium hydrogen phosphate + 5.8 ml of o-phosphoric acid (8.5% in water) / 1 l of water; mobile phase B: acetonitrile; UV detection at 268 nm; oven temperature: 50 ° C, injection volume: 3 µl, flow rate: 0.8 ml / minute; linear gradient in two stages: 10% of B → 37% of B (10 minutes), 37% of B → 80% of B (10 minutes), 10 minutes of maintenance time at 80% of B; purity:> 98% (Tr = 9.1 minutes).

Stage 3:

4- {4 - [({[4-Chloro-3- (trifluoromethyl) -phenyl] amino} carbonyl) amino] -3-fluorophenoxy} -N-methylpyridine2-carboxamide monohydrate

A reaction flask was charged with stirrer with 20.0 g of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide and 180 g of tetrahydrofuran as solvent. A solution of 18.7 g of 4-chloro-3-trifluoromethylphenyl isocyanate and 21.1 g of toluene was added dropwise in approximately 90 minutes at room temperature. The resulting solution was stirred for 3 hours until the reaction was complete. After this, 30 g of tetrahydrofuran and 7.8 g of methanol were added to the reaction mixture. Then 9.0 g of acetyl chloride in 15 minutes were added dropwise to the reaction mixture. After further stirring for approximately 2 hours the suspension was filtered and the solid was washed with tetrahydrofuran (18.2 g) and acetone (136.4 g). The solid was added to a mixture of acetone (268.6 g), water (55.8 g) and a solution of aqueous sodium hydroxide (8.2 g, 45% w / w) at 40 ° C. The mixture was stirred for an additional 30 minutes. Crystallization was then started by seeding with crystals of 4- {4 - [({[4-chloro-3- (trifluoromethyl) -phenyl] amino} carbonyl) amino] -3-fluorophenoxy} -N-methylpyridine-2- monohydrate. carboxamide After cooling to 20 ° C, 31.6 g of water were added. The suspension was cooled to about 3 ° C and stirred for 30 minutes. The product was filtered off, washed with a cold mixture of acetone (106 g) and water (44 g) and dried under reduced pressure (30 ° C, 8,000 pascals (80 mbar)). Thus, 31.8 g (83% of theory) of 4- {4 - [({[4-chloro-3- (trifluoromethyl) phenyl] amino} carbonyl) amino] -3-fluorophenoxy} -N -methylpyridine-2-carboxamide as white crystals.

1H NMR (500 MHz, METHANOL-d4): δ [ppm] = 2.94 (s, 3H), 6.96-7.01 (m, 1H), 7.05-7.11 (m, 2H ), 7.49-7.53 (m, 1H), 7.56-7.59 (m, 1H), 7.61-7.65 (m, 1H), 8.00-8.03 (m , 1H), 8.15-8.20 (m, 1H), 8.46-8.51 (m, 1H).

MS [ES]: m / e = 483 [M + H] +

HPLC: stationary phase: Eclipse XDB-C8 (150 mm long, 2.1 mm ID, 3.5 µm particle size); mobile phase A: 1.0 g of sodium salt of hexane-1-sulfonic acid + 1.0 ml of trifluoroacetic acid / 1 l of water; mobile phase B: acetonitrile; UV detection at 232 nm; oven temperature: 43 ° C, injection volume: 3 µl, flow rate: 0.5 ml / minute; 3-stage linear gradient: 5% of B → 36% of B (14.5 minutes), 36% of B → 44% of B (6 minutes), 44% of B → 80% of B (9.5 minutes ), 10 minutes *** of maintenance time at 80% of B; purity:> 99.5% (Tr = 25.7 minutes), relevant potential by-products: 4-amino-3-fluorophenol at TRR (relative retention time) of 0.10: normally <0.01% (2.6 minutes), 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide TRR 0.37: normally <0.01% (9.5 minutes); TRR 0.46 (4- (3-fluoro-4 - {[2- (methylcarbamoyl) pyridin-4-yl] amino} phenoxy) -methylpyridine-2-carboxamide): normally <0.15% (11.7 minutes ); TRR 0.69 (4- (3-fluoro-4 - {[(2-fluoro-4 - {[2 (methylcarbamoyl) pyridin-4-yl] oxy} phenyl) carbamoyl] amino} phenoxy) -N-methylpyridine- 2-carboxamide): normally <0.15% (17.7 minutes).

HPLC (trace analysis procedure for quantification of 4-amino-3-fluorophenol): stationary phase: X-Bridge Shield C18 (150 mm long, 3.0 mm ID, 3.5 µm particle size); mobile phase A: 1.5 g of potassium dihydrogen phosphate + 0.5 g of dipotassium hydrogen phosphate 1 l of water; mobile phase B: acetonitrile; UV detection at 228 nm; oven temperature: 50 ° C, injection volume: 3 µl, flow rate: 1.0 ml / minutes; 5 minutes of maintenance time at 5% of B, linear gradient in 1 stage: 5% of B → 80% of B (10 minutes), Tr of 4 amino-3-fluorophenol: 1.7 minutes, quantification against external standard of 4-amino-3-fluorophenol.

HPLC (trace analysis procedure for quantification of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide): stationary phase: X-Bridge Shield C18 (150 mm long, 3.0 mm ID, 3.5 µm particle size); mobile phase A: 1.5 g of potassium dihydrogen phosphate + 0.5 g of dipotassium hydrogen phosphate 1 l of water; mobile phase B: acetonitrile; UV detection at 228 nm; oven temperature: 50 ° C, injection volume: 3 µl, flow rate: 1.0 ml / minutes; linear gradient in 1 stage: 8% of B → 80% of B (15 minutes), Tr of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide: 7.0 minutes, quantification against external standard of 4- (4-amino-3-fluorophenoxy) -Nmethylpyridine-2-carboxamide.

Stage 4:

4- {4 - [({[4-chloro-3- (trifluoromethyl) -phenyl] amino} carbonyl) amino] -3-fluorophenoxy} -N-methylpyridine-2-carboxamide

10

fifteen

twenty

25

30

E11712881

07-14-2015

10.2 g of 4- {4 - [({[4-chloro-3- (trifluoromethyl) phenyl] amino} carbonyl) amino] -3-fluorophenoxy} -N-methylpyridine-2-carboxamide monohydrate were dried under reduced pressure ( 2,100 pascals (21 mbar)) at 90 ° C for 3 hours. Thus, 9.8 g of 4- {4 - [({[4-chloro-3- (trifluoromethyl) phenyl] amino} carbonyl) -amino] -3-fluorophenoxy} -N-methylpyridine-2-carboxamide were obtained as white crystals

P.f. 187-188 ° C

1H NMR (400 MHz, METHANOL-d4): δ [ppm] = 2.94 (s, 3H), 6.94-7.13 (m, 3H), 7.51 (d, 1H), 7, 58 (d, 1H), 7.61-7.67 (m, 1H), 8.01 (d, 1H), 8.17 (t, 1H), 8.45-8.53 (m, 1H) .

MS [ES]: m / e = 483 [M + H] +

HPLC: stationary phase: Eclipse XDB-C8 (150 mm long, 2.1 mm ID, 3.5 µm particle size); mobile phase A: 1.0 g of sodium salt of hexane-1-sulfonic acid + 1.0 ml of trifluoro acetic acid / 1 l of water; mobile phase B: acetonitrile; UV detection at 232 nm; oven temperature: 43 ° C, injection volume: 3 µl, flow: 0.5 ml / minutes; 3-stage linear gradient: 5% of B → 36% of B (14.5 minutes), 36% of B → 44% of B (6 minutes), 44% of B → 80% of B (9.5 minutes ), 10 minutes of maintenance time at 80% B; purity:> 99.5% (Tr = 25.2 minutes), relevant potential by-products: 4-amino-3-fluorophenol at TRR (relative retention time) of 0.10: normally <0.01% (2.5 minutes), 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide TRR 0.36: normally <0.01% (9.1 minutes); TRR 0.46 (4- (3-fluoro-4 - {[2- (methylcarbamoyl) pyridin-4-yl] amino} phenoxy) -methylpyridine-2-carboxamide): normally <0.15% (11.3 minutes ); TRR 0.69 (4- (3-fluoro-4 - {[(2-fluoro-4 - {[2 (methylcarbamoyl) pyridin-4-yl] oxy} phenyl) carbamoylamino} phenoxy) -N-methylpyridine-2- carboxamide): normally <0.15% (17.2 minutes).

HPLC (trace analysis procedure for quantification of 4-amino-3-fluorophenol): stationary phase: X-Bridge Shield C18 (150 mm long, 3.0 mm ID, 3.5 µm particle size); mobile phase A: 1.5 g of potassium dihydrogen phosphate + 0.5 g of dipotassium hydrogen phosphate 1 l of water; mobile phase B: acetonitrile; UV detection at 228 nm; oven temperature: 50 ° C, injection volume: 3 µl, flow rate: 1.0 ml / minutes; 5 minutes of maintenance time at 5% of B, linear gradient in 1 stage: 5% of B → 80% of B (10 minutes), Tr of 4 amino-3-fluorophenol: 1.7 minutes, quantification against external standard of 4-amino-3-fluorophenol.

HPLC (trace analysis procedure for quantification of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide): stationary phase: X-Bridge Shield C18 (150 mm long, 3.0 mm ID, 3.5 µm particle size); mobile phase A: 1.5 g of potassium dihydrogen phosphate + 0.5 g of dipotassium hydrogen phosphate 1 l of water; mobile phase B: acetonitrile; UV detection at 228 nm; oven temperature: 50 ° C, injection volume: 3 µl, flow rate: 1.0 ml / minute; linear gradient in 1 stage: 8% of B → 80% of B (15 minutes), Tr of 4- (4-amino-3-fluorophenoxy) -N-methylpyridine-2-carboxamide: 7.0 minutes, quantification against external standard of 4- (4-amino-3-fluorophenoxy) -Nmethylpyridine-2-carboxamide.

Claims (1)

image 1 image2